Two other interesting points from the motion. First, the computer that MediaSentry detected "sharing" files on the relevant date was located in Rhode Island -- which would seem to preclude the application of Massachusetts private investigator or wiretap law to its activities. (MediaSentry itself had no physical presence in Massachusetts.) And second, it appears that Massachusetts dropped whatever inquiry it was making into MediaSentry's possible status as a private investigator requiring a license under state law. According to the labels' motion, MediaSentry received a letter from the Massachusetts State Police on this issue on January 2, 2008, to which it responded on January 10. Since then, nothing. While there's no indication in the record that Massachusetts has formally dropped its inquiry, its silence over the last 18 months speaks volumes.
Plaintiffs' Opposition to Motion to Suppress MediaSentry evidence
UPDATE: Sidney Rosenzweig at the Progress & Freedom Foundation's blog has a very interesting post addressing the potentially far-reaching and dangerous effects were Tenenbaum's arguments under federal wiretap laws to be accepted:
In sum, Nesson (through Tenenbaum) does a butcher job on wiretapping law to such a degree that he ought to be ashamed to be advancing these arguments. The effect of his proposed construction of law is not merely to expose countless IT professionals and computer hobbyists to criminal penalties, but also to impair law enforcement by preventing them from employing certain non-warrant-requiring surveillance techniques they have been using lawfully for decades.